Spin-orbit coupling and electric-dipole spin resonance in a nanowire double quantum dot

TL;DR

This paper investigates how spin-orbit coupling enables electric-dipole spin resonance in a nanowire double quantum dot, analyzing the mechanisms, transition rates, and relaxation effects influenced by magnetic fields and material properties.

Contribution

It provides a detailed analysis of EDSR mechanisms in nanowire double quantum dots and explores the impact of strong SOC on electron coherence and relaxation processes.

Findings

EDSR can be driven via SOC-induced pseudospin mixing and interdot tunneling.

Transition rates depend strongly on magnetic field and interdot distance.

Spin-flip relaxation is suppressed by phonon bottleneck effect in strong SOC materials.

Abstract

We study the electric-dipole transitions for a single electron in a double quantum dot located in a semiconductor nanowire. Enabled by spin-orbit coupling (SOC), electric-dipole spin resonance (EDSR) for such an electron can be generated via two mechanisms: the SOC-induced intradot pseudospin states mixing and the interdot spin-flipped tunneling. The EDSR frequency and strength are determined by these mechanisms together. For both mechanisms the electric-dipole transition rates are strongly dependent on the external magnetic field. Their competition can be revealed by increasing the magnetic field and/or the interdot distance for the double dot. To clarify whether the strong SOC significantly impact the electron state coherence, we also calculate relaxations from excited levels via phonon emission. We show that spin-flip relaxations can be effectively suppressed by the phonon bottleneck effect even at relatively low magnetic fields because of the very large $g$-factor of strong SOC materials such as InSb.